Yes, this is still a problem with the Unibody MBPs (at least mine; n = 1). I convinced an authorized Apple service ctr to replace my logic board on my 3,1 because of the same issue (in addition to the USB power problem); the new board was the same.
A variable resistor will work, but some of the designs are more than resistors in series. There are some combinations of resistors in parallel that are said to achieve different sound properties. As with all in audiophilia, listen for yourself before deciding the merits.
Yes, this is limited to low impedance 'phones - IEMs mostly. Generally speaking, the higher impedance and lower sensitivity IEMs are made to be powered by a dedicated, often complex headphone amplifier (not the one in the MBP), but an impedance adapter "solves" the problem.
For those who stumble upon it, I think that the 65 USD that Etymotic charges for their ER-4P/S converter is straight robbery, akin to earlier Apple RAM prices. Even Head Room, which is a great company, is charging far more than the thing is worth at 50 USD - a couple of bucks in parts and someone's 2 minutes of soldering time - seriously.
A variable resistor will work, but some of the designs are more than resistors in series. There are some combinations of resistors in parallel that are said to achieve different sound properties. As with all in audiophilia, listen for yourself before deciding the merits.
Yes, this is limited to low impedance 'phones - IEMs mostly. Generally speaking, the higher impedance and lower sensitivity IEMs are made to be powered by a dedicated, often complex headphone amplifier (not the one in the MBP), but an impedance adapter "solves" the problem.
For those who stumble upon it, I think that the 65 USD that Etymotic charges for their ER-4P/S converter is straight robbery, akin to earlier Apple RAM prices. Even Head Room, which is a great company, is charging far more than the thing is worth at 50 USD - a couple of bucks in parts and someone's 2 minutes of soldering time - seriously.
